SelectBeckley Airport Springfield, Ohio 45502
937

- 398

- 0313 

## SelectTech GeoSpatial
EH

- 4 VTOL Technical Manual
Rev: 1.9
Date: 17 March 2015

SelectTech GeoSpatial LLC Springfield Beckley Airport Springfield, Ohio 45502
937

- 398

- 0313EH

- 4 Technical Manual

SelectTech GeoSpatial© 2015 Page 1 

### Contents

I. Introduction

................................ ................................ ................................ ................................ .......... 3

II. sUAS Basics

................................ ................................ ................................ ................................ ............ 4

III. Component s

................................ ................................ ................................ ................................ ...... 5

Airframe

................................ ................................ ................................ ................................ .................... 5
Power and Control System

................................ ................................ ................................ ....................... 6
Motors and Electronic Speed Controllers

................................ ................................ ................................ . 8
Propeller Assembly

................................ ................................ ................................ ................................ ... 9

Controls

................................ ................................ ................................ ................................ ................... 10
Primary Radios

................................ ................................ ................................ ................................ ........ 12
Telemetry

................................ ................................ ................................ ................................ ................ 14
Autopilot

................................ ................................ ................................ ................................ ................. 14

IV. VTOL Flight Characteristics

................................ ................................ ................................ ............. 17

Manual Controls

................................ ................................ ................................ ................................ ...... 18

Telemetric C ontrols

................................ ................................ ................................ ................................ . 19
Autopilot Flight Modes

................................ ................................ ................................ ........................... 20

V. Flight Safety

................................ ................................ ................................ ................................ ......... 24
General Flight Safety Guidelines

................................ ................................ ................................ ............. 24

Spotters:

................................ ................................ ................................ ................................ .............. 24
Operating Paramete rs

................................ ................................ ................................ ............................. 24
General Preflight Checklist

................................ ................................ ................................ ...................... 25

VI. Available Sensor Packages

................................ ................................ ................................ .............. 27

VII. Maintenance

................................ ................................ ................................ ................................ ... 28
Recommended Spare Components

................................ ................................ ................................ ........ 28

Aircraft Maintenance

................................ ................................ ................................ .............................. 29
Batteries and Safe Charging

................................ ................................ ................................ .................... 30
Battery Maintenance

................................ ................................ ................................ .............................. 32

 Civil UAS

................................ ................................ ................................ ................................ ...... 34

 Public UAS

................................ ................................ ................................ ................................ ... 34

 Model Aircraft

................................ ................................ ................................ ............................. 34EH

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SelectTech GeoSpatial© 2015 Page 2 Table of Figures

Figure 1 EH

- 4 Airframe

................................ ................................ ................................ ................................ .. 5 Figure 2 EH

- 4 Block Diagram

................................ ................................ ................................ ......................... 6 Figure 3 EH

- 4 Motor

................................ ................................ ................................ ................................ ...... 8 Figure 4: Propeller / Motor Assembly

................................ ................................ ................................ ........... 9 Figure 5: Propeller Orientation / Motor Rotation

................................ ................................ ........................ 9 Figure 6: Control Signal Diagram

................................ ................................ ................................ ................ 10 Figure 7: Spectrum Satellite Receiver

................................ ................................ ................................ ......... 12 Figure 8: Spektrum DX8 Transmitter

................................ ................................ ................................ .......... 13 Figure 9:3D Robotics Telemetry Transceiver

................................ ................................ .............................. 14 Figure 10: Pixhawk Autopilot

................................ ................................ ................................ ...................... 15 Figure 11: Command and Sensor Inputs

................................ ................................ ................................ ..... 16 Figure 12 Spektrum DX8 Transmitter

................................ ................................ ................................ ......... 18 Figure 13 Rotational rate is proportional to stick angle.

................................ ................................ ............ 19 Figure 14 Sensor Cassettes available for the EH

- 4

................................ ................................ ...................... 27 Figure 15 Typical Propeller Balancer

................................ ................................ ................................ ........... 30 Figure 16 Battery Analyzer

................................ ................................ ................................ .......................... 32 Figure 17 Battery Charger

................................ ................................ ................................ ........................... 33EH

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SelectTech GeoSpatial© 2015 Page 3 

## I. Introduction

Thank you for purchasing the EH

- 4 VTOL (Vertical Take

- off and Landing) small
Unmanned Aerial S ystem (sUAS). The EH

- 4 is specifically designe d for heavy duty industrial, public service and agricultural applications. The airframe is constructed from fibergla ss reinforced polyester resin and high impact engineered thermoplastic and can resist rough landings and challenging environments. This aircraft is also designed for ease of assembly / disassembly aiding in quick repairs and modifications. This operations manual will cover significant maintenance and flight operations details. Addition al references are added for context and deeper understanding of the technology relating to this aircraft.

Safety

Aircraft safety should to be constantly in the forefront of the pilot in charge (PIC) Observer and all other mission participants. The EH

- 4 is a serious aircraft that is designed for heavy

- duty applications. The EH

- 4 is not designed nor recommended for rec reational use. This aircraft uses very powerful Lithium Ion batteries that can seriously burn the operator if used improperly. The propellers on this aircraft and very sharp and when rotating can present a serious hazard. The same precaution used with ful l scale aircraft need to be observed. Many fail

- safe systems are included with this aircraft however, when not properly used this aircraft can be a dangerous projectile. This aircraft is also capable of flying in restricted airspace. As with and any
aircra ft, all precautions need to be taken to avoid interference with other aircraft. Thought this operations manual, safety items will be emphasized and bordered in yellow.EH

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SelectTech GeoSpatial© 2015 Page 4 

## II. sUAS Basics

sUAS used today fall into 3 main configuration categories:

 Fixed Wing

 Helicopter

 VTOL

There is no coincidence that the configuration categories look very similar to their full

scale counterpoints . All sUAS designs borrowed from previously existing airframes. VTOL’s (Quads, Hexes etc.) are newer designs that exist beca use of developments in motors, batteries
and sensor miniaturization.

This manual is d edicated to the EH

- 4 VTOL operations, maintenance and related accessories.

There are numerous benefits of sUAS operations that can mitigate safety concerns of manned
fl ight operations, manned ground operations, and added benefits unique to sUAS. Aside from the weight, speed, altitude, and operating perimeters offered by sUAS, the most important safety aspect is that sUAS are unmanned, greatly reducing loss

- of

- life and se rious injury risks. sUAS grant the user the ability to move closer to equipment without causing harm to either the structure being inspected or the personnel on the ground. Maneuverability allows for data output unseen in many industries.EH

- 4 Technical Manual

SelectTech GeoSpatial© 2015 Page 5 

## III. Components

T he ability for the EH

- 4 VTOL to launch and remain airborne relies on a number of systems and subsystems that must operate in concert. A short list of these systems includes :

 Airframe

 Power and Control System

 Motors

 Propeller Assembly

 Controls

 Primary Radi o s

 Autopilot

 Telemetry Radios

Airframe

The airframe of the EH

- 4 consists of a Top Plate

, Bottom Plate

, Legs
, Canopy and
f asteners . The top plate, bottom plate and legs are made from G

- 10 fiberglass composite and the canopy is made from high impact resistant Kydex® engineered thermoplastic. The airframe provides the basic structural members of the aircraft.

Figure 1 EH

- 4 AirframeEH

- 4 Technical Manual

SelectTech GeoSpatial© 2015 Page 6 Power and Control System

The power system provides electrical energy for the motors as well as all of the fli ght controls.
It consists of a Lithium Ion Polymer (L iPo ) b attery , polarized connectors, distribu tion harness and battery monitor. The battery requires special charging equipment as well as proper care to maintain the battery’s energy density. As with all L iPo batteries, special precautions need to b e in place as they can deliver high instantaneous currents. Additional information on b attery safety and maintenance is provided in Chapter IX

.

Pilot cont rol inputs sent from the transmitter to the receiver are combined with onboard sensor outputs by the autopilot (AP) . The AP generates speed control signals for the ESCs so the
motors maintain a stable flight platform.

Two

- way radio telemetry provides for additional aircraft control, mission parameters and feedback to the pilot about aircraft position, battery capacity, sensor health, etc.

Figure 2 EH

- 4 Block DiagramEH

- 4 Technical Manual

SelectTech GeoSpatial© 2015 Page 7

(a) Battery : A Lithium Ion battery, completely modular to allow for rapid battery changes between missions. (b) Power conne ctor/distributor : Provides power through polarized connectors

to components of the aircraft including the autopilot , radios and
ESCs /motors

. (c) Battery po wer indicator : Equipped with a visual indicator of battery health as well as a speaker for warning alerts. (d) Electronic Speed Controller (ESC) : Receives information from the AP and
converts it into a three

- phase control signal. This three

- phase signal dr ives the brushless motor to attain a specific number of revolutions per minute. (e) Motor : Four motors and propellers, M1 and M2 rotate counter clockwise
and M3 and M4 clockwise. (f) Autopilot : The EH

- 4 utilizes the Pixhawk autopilot (AP) by 3DRobotics

. The primary function of the Pixhawk is to monitor the orientation of the aircraft and drive the multiple motors to achieve stable flight. (g) Motor Safety Switch (Red) : Quick, constant blinking: performing system check, Please wait. Intermittent blinking: system ready. Press the safety button to activate. Solid: ready to arm. Proceed to the arming procedure. (h) Telemetry : This two

- way radio system provides a secondary method of controlling the aircraft, including flight path programming from a PC or
tablet. T ransmitt ing at 915 MHz it a lso transmits aircraft performance and position data to the ground station

. (i) Receiver : S ends the pilots control inputs (the sticks) to the AP. (j) Buzzer : Provides audio signals to indicate the arming status of the AP

. (k) GPS/Compass : Determines the orientation of the aircraft with gyroscopes
and a magnet ometer . This data is interpreted by the autopilot and adjustments are made to ensure accuracy for transmitter and telemetry
based controls. (l) Transmitter : S ends the pilots control inputs (the sticks) to the r eceiver
onboard the aircraft to control the roll, pitch, yaw, and altitude of the EH

- 4. (m) Ground Control and Telemetry : This can be a Windows PC, iOS/Android/Windows based Tablet, or other optional supported devices provided by the manufacturer that can collect data from the aircraft during flight, including altimeter readings, GPS location, battery life, and other important data.EH

- 4 Technical Manual

SelectTech GeoSpatial© 2015 Page 8 Motors and Electronic Speed Controllers

The function of the ESCs is to take information from th e autopilot and turn it into a 3

- phase control signal. This 3

- phase signal drives the brushless motor s to attain a rotational speed to a certain number of revolutions per minute (RPM). Full battery power from the power system is connected to the input of t he ESC as well as the signal output from the autopilot . The three phase ESC output wires connect to the three phase wires on the motor. Motor speed is a direct
function of information from the autopilot system.

The brushless motors on the EH

- 4 are out runner style

. Out runner motors are 3 phase motors with the rotati ng section on the outside of the motor

. The rotor is lined with powerful magnets and the stator a wire

- wound pole set with the winding count corresponding to the magnet
count. The motors are controlled and driven via an electronic speed control (ESC). The ESC capacity is matched to the maximum power draw of the motor at full load.

The EH

- 4 has a motor on each arm

.

Figure 3 EH

- 4 MotorEH

- 4 Technical Manual

SelectTech GeoSpatial© 2015 Page 9 Propeller Assembly

The propeller translates motor speed and to r que to lift. The p ropeller s provided with the EH

- 4 are matched to the weight and payload of the aircraft. Length, pitch and speed are critical for
maximum performance

. Changing the propeller size may adversely af fect flight characteristics
and duration. Also part of the propeller assembly is the h ub, washer and retaining nut. These
items are precisely sized to the propeller and need to remain tight at all times.

To avoid excessive vibration , the propeller s must b e balanced before installation. Should a nick or chip occur on a propeller, it must be replaced prior to the next flight. Most importantly each propeller should be inspected for damage and the retaining nut inspected for tightness before
each mission.

Figure 4 : Propeller / Motor Assembly

F igure 5 : Propeller Orientation / Motor RotationEH

- 4 Technical Manual

SelectTech GeoSpatial© 2015 Page 10 Controls

The controls of the EH

- 4 include: primary radio s , telemetry radio s , and autopilot. The primary radio opera tes in the 2.4 MHz band and uses spread

- spectrum modulation to minimize
interference

. The primary radio transmitter provides pilot command signals that give flight
instructions to the aircraft . The primary radio receiver onboard the aircraft receives and
decodes the signals in to flight commands. These commands are sent to the autopilot for mixing with data from the onboard sensors. In combination, the resultant control signals are fed to the
ESC s as commands to each motor.

Both ground and aircraft radios have antennas that should not be blocked or interfered with during flight operations. Before every flight, the radio system should be checked for reliable
connection of key maneuvers close to ground as outlined in the preflight checklist

.

Figure 6 : Control Signal DiagramEH

- 4 Technical Manual

SelectTech GeoSpatial© 2015 Page 11 (a) The pilot sends attitude commands to the aircraft using the transmitter. In this example,
she will send controls to thrust all motors resulting in an upward climb. (b) The receiver collects pilo t commands from the transmitter and pushes it to the autopilot. (c) Simultaneously , the g round station telemetry control sends commands to the aircraft
via telemetry. Many variables can be used to control the aircraft, including remaining battery life, return

- to

- home failsafe conditions , geofencing, and any other parameters monitored by the AP . In this example, the computer directs the aircraft to stop climbing after reaching 400’ above ground level ( AGL )

. (d) The telemetry continually monitors the onboard altimete r/ GPS for altitude information. (e) If the aircraft exceeds 400’ AGL, the AP will hold the aircraft at the set maximum altitude
of 400’ AGL. (f) Data about the health, performance and position of the aircraft are sent to the ground
station. (g) The autopilot sensor data are collected and analyzed . The resulting commands for power needed are sent to the ESCs to control the individual motor speeds. (h) In this example, the aircraft attempted to rise above 400’ AGL so the autopilot prevented the EH

- 4 from continuing to climb by overriding the primary radio

The system of controls for the UAS is very complicated. The above example takes place every
20 milliseconds from a mult itude of components, all at the same time. The preflight procedures requires the PIC to set safety parameters for the UAS, and therefore manual controls may be overridden; it is the duty of the PIC to be in control of the UAS, which means
the PIC must unde rstand all autonomous controls set during the preflight procedures.

For example, if the gyroscope is set to send commands to the motors to account for level hovering near ground and the PIC fails to disengage before picking up the UAS, the gyroscope
will detect the movement, switch on the motors, and cause injury/harm to the person picking up the UAS. Always be conscious of the manual and autonomous controls, failsafes, and safety procedures.EH

- 4 Technical Manual

SelectTech GeoSpatial© 2015 Page 12 Primary Radio s

The Primary R adio s , also considered the main flight radio s , are a pair of Spectrum TM radios. The pilot uses the DX8 transmitter to command the aircraft. The SPM9645 PPM sum receiver
communicates those commands directly to the AP

.

Spektrum systems are distinguished in that they use direct

- sequence spread spectrum (DSSS) technology on the 2.4 GHz ISM band. Spektrum refers to their technology as "Digital Spectrum Modulation." Each transmitter has a globally unique identifier (GUID), to which receivers are bound, ensuring that no transmitter will interfere with other nearby systems. This work s in a manner that both transmitter and receiver are constantly changing through the different frequencies of the 2.4 GHz range. The Spektrum system is also unique in that it offers "Model Match" in which each transmitter program for a particular flight mo del is bound to one and only one receiver. The AR8000 supplied with the DX8 has a satellite receiver that is connected directly to the Pixhawk autopilot. The SPM9645 is bound to a Spektrum AR8000 to provide unique receiver identification. The AR8000 is not installed on the EH

- 4. It is used solely to bind the SPM9645 to a specific radio control transmitter.

Figure 7 : Spectrum Satellite Receiver
The switches on the DX8 transmitter are programmed to provide specific instructions to the aircraft simply by changing a switch position. A three position switch commands the AP to enter one of three operating modes. A two position switch commands the AP t o begin a sequence of

pre

- programmed maneuvers. A different two position switch commands the AP to return the
aircraft to the initial take off location as an added failsafe

.EH

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SelectTech GeoSpatial© 2015 Page 13 Figure 8 : Spektrum DX8 TransmitterEH

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SelectTech GeoSpatial© 2015 Page 14 Teleme try

Telemetry (Data in both directions) is provided by a 915MHz 3DR radio set. The radio uses Frequency Hopping Spread Spectrum (FHSS) modulation and can broadcast a number of data channels between air and ground operations. The power output can be set by the main flight control system. The unit connects to the AP via a serial connection and ground via a 9 15
antenna. More can be found online: http://store.3drobotics.com/products/3dr

- radio

Figure 9 :3D Robotics Telemetry Transceiver
Autopilot

The primary function of the Pixhawk autopilot (AP) is to monitor the orientation of the aircraft and drive the multiple motors to achieve stable flight. The user’s control input s are then used to adjust the aircraft away from a stable orientation by pitching, rolling and yawing (spinning) the
EH

- 4 . These actions cause the aircraft to move in different directions so that it can effectively be flown. T o achieve stable flight, data from a magnetometer, gyroscopes, accelerometers, GPS and a pressure sensor are fused together thousands of times a second. This information is then used to make decisions on how to achieve the pilot’s desired orientation.

The Pixhawk autopilot (AP) is an open source product manufactured by 3D Robotics. Core
features include a real

- time operating system, powerful processor, integration of sensors and other sensor technology, multithreading, a fully programmable environment for flexibility in creating be haviors and missions, precise timing between components, and a large community of developers to allow for expanded capability.

The P ixhawk System includes:

 Pixhawk autopilot

 Audio Warning System

 Safety

– Arming Switch

 3DR power module with XT60 connectors and 6

- position connector cable

 Extra 6

- position cable to connect a 3DR GPS+Compass module

 Standard m icro USB cable

 SD card and adapterEH

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SelectTech GeoSpatial© 2015 Page 15  I2C splitter module with cable

Autopilot Features :

 Advanced 32 bit ARM Cortex® M4 Processor running NuttX RTOS , an open

- source operating system used for real time microcontroller environments

 14 PWM/servo outputs (8 with failsafe and manual override, 6 auxiliary, high

- power compatible)

 A multitude of connectivity options

 Built

- in fail safes for manual overriding, mixin g of manual and autopilot, and dedicated processing and power

 Redundant inputs for power

 User

- friendly safety controls

 LED indicator

 Audio warning signal

 Long

- time, fast logging of flights onboard with microSD input

Figure 10 : Pixhawk Autopilot

Additional information on the Pixhawk AP can be found online at: https://store.3drobotics.com/products/3dr

- pixhawk

.EH

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SelectTech GeoSpatial© 2015 Page 16 Figure 11 : Command and Sensor InputsEH

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SelectTech GeoSpatial© 2015 Page 17 

## IV. VTOL Flight Characteristics

In order for a VTOL to fly, lift and balance must be created via the o n board motors. To fly in a stable hover, the lift at each motor has to be precisely balanced taking into account the

surro unding environment. Because of the number of variables associated with VTOL flight, an autopilot becomes critical in keeping the aircraft balanced and in flight. Using a number gyroscopes and accelerometers in the pitch, roll and yaw axes along with ground contr ol input, the aircraft can maintain controlled flight.

Lift and flight are created with large, balanced propellers mounted on each motor. The propellers rotate at high speed delicately controlled via individual electronic speed controls (ESC).

Pitch mov ement and resultant forward motion is achieved by minutely slowing the front

motors and speeding up the rear motors.

Figure 12: Force DiagramEH

- 4 Technical Manual

SelectTech GeoSpatial© 2015 Page 18 In order to maintain flight stability and execute the mission, the autopilot receives its
commands from a number of sources ( see figure 10 ) :

 Primary Radio Transmitter

 Secondary Radio (Telemetry)

 Internal Sensors

 On board memory

Manual Controls

The primary radio sends flight commands that principally control Yaw, Pitch, Rill and Throttle.
Additional command s may also be managed by the primary radio. Proportional c ont rol inputs are accomplished via two joy stick controls. The control transmitter is configured in what is known as mode 2. Mode 2 has the throttle and yaw on the left stick and the pitch and roll on the right stick as seen in figure 11

.

Figure 12 Spektrum DX8 TransmitterEH

- 4 Technical Manual

SelectTech GeoSpatial© 2015 Page 19 Figure 13 Rotational rate is proportional to stick angle.

Telemetric Controls

The secondary radio (telemetry) is used for sending aircraft parameters to the ground control station and can also be used as a flight controller as described above. Commands are sent via the ground control station transceiver. The secondary radio is also used to upload mission parameters into t he on board autopilot memory.

An array of internal sensors are incorporated into the autopilot. These sensors detect and
measure the aircraft altitude and adjust the flight characteristics according to their inputs in concert with program m ed algorithms. T he installed sensors include:

 Yaw, Pitch and Roll Gyroscopes

 Yaw, Pitch and Roll Magnetometers

 Yaw, Pitch and Roll Accelerometers

 Magnetic Compass

 GPS receiver

 Barometric Altimeter

On board memory of mission parameters also dictates flight parameters and resultant modes. Activating the flight mode memory is preformed manually via the primary ground radio. Commands from memory can be overridden via the primary ground radio.EH

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SelectTech GeoSpatial© 2015 Page 20 Autopilot Flight Modes

T he following flight modes are factory configured on the EH

- 4. For detailed information on flight modes, please go to http://copter.ardupilot.com/wiki/flight

- modes/

.

St abilize Mode (manual)

• Pilot’s roll and pitch input control the lean angle of the UAV. When the pilot releases the roll and pitch sticks the vehicle automatically levels itself.

• Pilot will need to regularly input roll and pitch commands to keep the ve hicle in place as it is pushed around by the wind.

• Pilot’s yaw input controls the rate of change of the heading. When the pilot releases the yaw stick the vehicle will maintain its current heading.

• Pilot’s throttle input controls the average motor spe ed meaning that constant adjustment of the throttle is required to maintain altitude. If the pilot puts the throttle completely down the motors will go to their minimum rate (MOT_SPIN_ARMED) and if the vehicle is flying it will lose attitude control and t umble.

• The throttle sent to the motors is automatically adjusted based on the tilt angle of the vehicle (i.e. increased as the vehicle tilts over more) to reduce the compensation the pilot must do as the vehicle’s attitude changes. Altitude Hold Mode (Al t Hold) When altitude hold mode (aka AltHold) is selected, the throttle is automatically controlled to maintain the current altitude. Roll, Pitch and yaw operate the same as in Stabilize mode meaning that the pilot directly controls the roll and pitch lean angles and the heading. Automatic altitude hold is a feature of many other flight modes (Loiter) so the information here pertains to those modes as well. Note: The flight controller uses a barometer which measures air pressure as the primary means
for determining altitude (“Pressure Altitude”) and if the air pressure is changing in your flight area due to extreme weather, the copter will follow the air pressure change rather than actual
altitude. The pilot can control the climb or descent rate of the ve hicle with the throttle stick.

• If the throttle stick is in the middle (~40%

- 60%) the vehicle will maintain the current
altitude.

• Outside of the mid

- throttle deadzone (i.e. below 40% or above 60%) the vehicle will descend or climb depending upon the d eflection of the stick. When the stick is completely down the copter will descend at 2.5m/s and if at the very top it will climb by 2.5m/s.EH

- 4 Technical Manual

SelectTech GeoSpatial© 2015 Page 21 Loiter Mode

Loiter Mode automatically attempts to maintain the current location, heading and altitude. The pil ot may fly the copter in Loiter mode as if it were in manual. Releasing the sticks will continue to hold position. Good GPS position, low magnetic interference on the compass and low vibrations are all important in achieving good loiter performance. The pi lot can control the copter’s position with the control sticks.

• Horizontal location can be adjusted with the Roll and Pitch control sticks with the default maximum horizontal speed being 5m/s. When the pilot releases the sticks the copter
will slow to a stop.

• Altitude can be controlled with the Throttle control stick just as in AltHold mode

• The heading can be set with the Yaw control stick. Return to Launch (RTL) Return To Launch is a switch selection on a factory configured primary radio as shown in figure
8.
RTL is a GPS

- dependent move, so it is essential that GPS lock is acquired before attempting to use this mode. Before arming, ensure that the APM’s blue LED is solid and not blinking. For the GPS+Compass module, the LED will be blinking blue when GPS is locked. RTL will command the copter to return to the home position, meaning that it will return to the location where it was armed. Therefore, the home position is always supposed to be your copter’s actual GPS takeoff location, unobstructed and awa y from people. If you get GPS lock
and then ARM the EH

- 4, the home position is the location the EH

- 4 was in when it was armed. This means if you execute an RTL, it will return to the location where it was armed. Warning: In RTL mode the flight controller u ses a barometer which measures air pressure as the primary means for determining altitude (“Pressure Altitude”) and if the air pressure is changing in your flight area, the copter will follow the air pressure change rather than actual altitude

Auto Mode

In Auto mode the EH

- 4 will follow a pre

- programmed mission script stored in the autopilot which is made up of navigation commands (i.e. waypoints) and “do” commands (i.e. commands that do not affect the location of the copter including triggering a camera shutter).

AUTO mode incorporates the altitude control from AltHold mode and position control from Loiter mode and should not be attempted before these modes are flying well. All the same requirements apply including ensuring that vibration levels and c ompass interference levels are acceptable and that the GPS is functioning well including returning an HDOP of under 2.0.EH

- 4 Technical Manual

SelectTech GeoSpatial© 2015 Page 22 AUTO is programmed as a switch setting on a factory configured primary radio as shown in figure 8. If starting the mission while the copter is on the ground the pilot should ensure the throttle is down, then switch to the Auto flight mode, then raise the throttle. The moment that the throttle is raised above zero, the copter will begin the mission. If starting the mission from the air the mission will begin from the first command the moment
that the switch is moved to Auto. If the first command in the mission is a take

- off command but the vehicle is already above the take

- off command’s altitude the take

- off command will be
considered c ompleted and the vehicle will move onto the next waypoint. At any time the pilot can retake control from the autopilot by returning the flight mode switch to another flight mode such as Stabilize or Loiter. If the pilot then switches to AUTO again, the
mission will restart from the first command. During the mission the pilot’s roll, pitch and throttle inputs are ignored but the yaw can be overridden with the yaw stick. This allows the pilot to for example aim the nose of the copter (which might have a h ard mounted camera on it) as the copter flies the mission. The autopilot will attempt to retake yaw control as the vehicle passes the next waypoint. Missions can be entered, amended through the Mission Planner’s Flight Plan screen. Please
refer to the 3D Robotics Mission Command List wiki page for a full list of supported commands along with a short description of each. Ending a Mission Missions should normally have an RTL as their final command to ensure the copter will return after the mission completes . Alternatively the final command could be a LAND with a different location. Without a final RTL or LAND command the copter will simply stop at the final waypoint and the pilot will need to retake control with the transmitter. Remember that when using RT L, the copter will return to the “home” position which is the location where the copter was armed. As the copter touches down at the end of the mission the pilot should move the throttle to zero at which point the autopilot will disarm the motors if it als o believes that it has landed. Other AutoPilot flight modes may be configured by the PIC as mission parameters dictate:

Acro Mode

Acro

- mode (Rate mode) uses the RC sticks to control the angular velocity of the copter.
Release the sticks and the vehicle will maintain its current attitude and will not return to level. Acro mode is useful for aerobatics such as flips or rolls, or FPV when smooth and fast control is
desired.EH

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SelectTech GeoSpatial© 2015 Page 23 Sport Mode

Sport

- mode is also known as “rate controlled stabilize” plus Altitude Hold.

Drift Mode

Drift

- Drift Mode allows the user to fly a multi

- copter as if it were a plane with built in
automatic coordinated turns.

Guided Mode

Guided

- mode is a capability of APM: Copter to dynamically guide the copter to a target
loc ation wirelessly using a telemetry radio module and ground station application. This page provides instructions for using guided mode

Circle Mode

Circle

- will orbit a point of interest with the nose of the vehicle pointed towards the center

Position Mode

Position

- is the same as loiter mode, but with manual throttle control. This means that, in position mode, the copter maintains a consistent location and heading, while allowing the operator to control the throttle manually.EH

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SelectTech GeoSpatial© 2015 Page 24 

## V. Flight S afety

Although sUAS are much safer than larger aircraft, and certainly safer than climbing and inspecting structures without the aid of any aircraft, it is still considered to be an aircraft and must always uphold the highest of safety procedures. This se ction will outline general safety measures to take with every mission. Additionally, an example checklist is provided to prepare and execute before every mission. This checklist is catered to the specific mission types of each client.

General Flight Safety Guidelines

The operation of any flying machine whether remote controlled or not can be dangerous. It is very important that you observe all necessary safety precautions before (and after) flying. A safety check list is provided at the end of this m anual for your reference; please make sure you use it.



### Spotters:

 Before a flight, the pilot must insure that the spotter understands his/her duties and expectations.

 A spotter should be used to assist in monitoring the surrounding airspace for manned aircraft whenever a flight is expected to exceed 400 feet above the ground and that operation is expected to be in proximity to known manned aircraft traffic such as at a mixed

- use facility or within three miles of an airport.

 The spotter must have suffic ient visual acuity and be mature enough to take this responsibility very seriously.

 A spotter should also be prepared to assist his/her pilot in the event that another model aircraft or spectators become endangered or in turn are perceived to be a danger t o the pilot or the pilot’s model aircraft.

Operating P ara meters

The operators must survey the area before any operation for obstructions, hazards, or anything
unusual

. No mission should be conducted unless a safe environment can be determined.EH

- 4 Technical Manual

SelectTech GeoSpatial© 2015 Page 25 General Preflight Checklist

Physical Examination

Airframe for damage

Motor mounting for loose or missing hardware

Motor power leads for chaffing

A utopilot wiring for loose connectors or wire damage Battery condition and charge level
Main Radio Connections Other electrical/mechanical

On Site Safety Briefing

Site Survey Selection of operating area and alternate Crew Makeup Crew Briefing Space Safety Barrier
Communications
Weather Check Refueling Procedure Payload Installation and Operation Failsafe procedures and operations

AP Calibration

Compass Accelerometer/ Magnetometer Radio (Yaw/Pitch/Roll/Throttle)
Modes
Fail Safe

Arm Aircraft

Battery Tone

– good Status Light

– greenEH

- 4 Technical Manual

SelectTech GeoSpatial© 2015 Page 26 Set Arm Button

- on Arm Tone 1

– good

Arm Tone 2

– good
Start Motors

- Idle Flight Checks

Manual launch and hover
Yaw Check
Pitch Check
Roll Check
Throttle Check

Begin Mission

End Mission

Dis Arm Aircraft
Set Arm Button

- off Disconnect and remove battery Physical InspectionEH

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SelectTech GeoSpatial© 2015 Page 27



## VI. Available Sensor Packages

A variety of sensor packages are available for attachment to the EH

- 4. All packages are mounted on an easy to remove cassette plate. Each sensor package contains its own independent power source. Currently available sensor packages are:

 GoPro Camera/Gimbal

 Garman Camera with GeoSpatial Tagging

 Forthwing ® NIR Agriculture Camera

 FLIR Tau Infrared Camera

 Other custom payloads

Sensor packages can utilize serial connections to the UAS, allowing the PIC to control some

compon ents of the sensors with telemetry or transmitter controls. Contact SelectTech GeoSpatial for additional operational and technical details for sensor and payload integration.

Figure 14 Sensor Cassettes available for the EH

- 4EH

- 4 Technical Manual

SelectTech GeoSpatial© 2015 Page 28 

## VII. Maintenance

Recommended Spare Components

Quantity Description

2 Motors, NeuMotor 725 RPM/Volt or equal

4 Propeller Sets, 11 x 5.5 (APC LP 11055 EP/E)

1 Landing Gear Set

1 Canopy/Cover

1 Airframe Set

1 Electronic Speed Control, Castle 35 Amp Quad

1 Spektrum AR8000 DSMX Receiver
10 10

- 32 x 3/8 Aluminum Socket Head Screws

10 10

- 32 x 3⁄4 long 1⁄4 Hex Aluminum Spacer

2 Batteries, LiPo 4S 14.8V 5600mAh 60C

4 M3x0.5 self

- locking propeller nutsEH

- 4 Technical Manual

SelectTech GeoSpatial© 2015 Page 29 Aircraft Maintenance

Regular maintenance is required on a regular basis. The chart below indicates the major system areas that require maintenance attention.

In order to reduce propeller generated vibrations, a balance analysis needs to be completed on each propeller. Balancing n eeds to be completed upon initial installation, or after a hard landing that impacts the propellers.EH

- 4 Technical Manual

SelectTech GeoSpatial© 2015 Page 30 Figure 15 Typical Propeller Balancer

Batteries and Safe C harging

The EH

- 4 uses Lithium Polymer rechargeable batteries as a power source. These batteries have been chosen for their high power density.

Lithium Polymer Battery Safety (From National Renewable Energy Laboratory (NREL ) :

Battery technology is at the hear t of much of our technological revolution. One of the most prevalent rechargeable batteries in use today is the Lithium

- ion battery.

Although lithium

- ion batteries are very common there are some inherent dangers when using
ANY battery. Lithium cells are like any other technology

– if they are abused and not used for their intended purpose catastrophic results may occur, such as: first

- , second

- , and third

- degree burns, respiratory problems, fires, explosions, and even death. Please handle the lithium

- ion batteries with care and respect.

User Safety Precautions

Short

- Circuiting

• When the battery is not in use, you MUST disconnect the battery from the battery connector. When the battery is connected to the battery connector, do not leave unattended since the two wires with the alligator clips can touch which will heat up the batter y. Short circuiting will damage the battery and generate heat that can cause burns.EH

- 4 Technical Manual

SelectTech GeoSpatial© 2015 Page 31 • Don't leave the battery in the charger once it is fully charged. The battery charger will flash on and off with a red indicator light every 20 seconds when the battery i s fully charged. Overcharging the batteries will not increase the performance and could lead to damage.

Disassembly • Never disassemble a battery as the materials inside may be toxic and may damage skin and clothes.
• DO NOT place a battery in fire; th is may cause the battery to rupture. The electrolyte is very flammable and if an ignition source exists, then fire and even an explosion could result.
NEVER place batteries in water, as this may cause the battery to rupture and release poisonous gasses. Fu rthermore, when the electrolyte is combined with water, there is the potential for hydrofluoric acid to form

– an extremely toxic and corrosive substance.

Soldering • Never solder anything directly to a battery. This can destroy the safety features of the battery by damaging the safety vent inside the cap.

Charging • Never charge with an unspecified charger or specified charger that has been modified. This can cause breakdown of the battery or swelling and rupturing.
• Never attempt to charge a battery which has been physically damaged.
• Avoid designing airtight battery compartments. In some cases, gases (oxygen, hydrogen) may be given off, and there is a danger of a battery bursting or rupturing if ignited by sparks

. • Do not use a battery in an appliance or purpose for which it was not intended.

Safety Procedures • If the foil packaging on the battery does break, vent the room and leave area.
• If a fire starts, call the fire department immediately. The only ex tinguisher that will work on a Lithium

- ion Battery fire is a Class D Fire Extinguisher or Dry Sand or Dry Table Salt.

Battery Disposal Lithium

- ion batteries are found in many electronics like laptops, digital cameras, power tools, and cordless phones. T hese batteries are very popular because they can be recharged and because they are able to supply power for a long period of time. However, even lithium

- ion batteries reach a point where they can no longer hold a charge and need to be disposed of. When thi s time comes, it is important to know how to recycle the battery, and not simply put it in a trash can. Determine your states recycling policy.EH

- 4 Technical Manual

SelectTech GeoSpatial© 2015 Page 32 There are many reasons to recycle these batteries rather than throw them away where they may end up in a regula r landfill.

Battery Maintenance

In order to maintain flight batteries in top condition, they should be continuously monitored. Prior to each flight and during the mission, the voltage should be checked. At no time should the voltage be allowed to go below 3.2 volts per cell. For safety reasons, landing voltages should be at 25% full charge (13.8 Volts). Flight voltages can be monitored via telemetry received at the ground station.

Figure 16 Battery AnalyzerEH

- 4 Technical Manual

SelectTech GeoSpatial© 2015 Page 33 Figure 17 Battery ChargerEH

- 4 Technical Manual

SelectTech GeoSpatial© 2015 Page 34 FAA statement o n Unmanned Aircraft Systems ( Reprinted From FAA Site)

Safety is the FAA's top mission, and the agency maintains the world's safest aviation system. The FAA first authorized use of unmanned aircraft in the National Airspace System (NAS) in
1990.

Today, unmanned aircraft are flying in the NAS under very controlled conditions, performing border and port surveillance by the Department of Homeland Security, helping with scientific

resea rch and environmental monitoring by NASA and NOAA, supporting public safety by law enforcement agencies, helping state universities conduct research, and supporting various other missions for public (government) entities. Operations range from ground level to above 50,000 feet, depending on the specific type of aircraft. However, UAS operations are currently not authorized in Class B airspace (PDF), which exists over major urban areas and contains the highest density of manned aircraft in the National Airspace System.

There are three types of unmanned aircraft system operations: Civil, Public and Model Aircraft.

 Civil UAS

Obtaining a Special Airworthiness Certificate in the experimental category for a particular UAS is currently the only way civil operators of unmanne d aircraft are accessing the NAS. Experimental certificate regulations preclude carrying people or property for compensation or hire, but do allow operations for research and development, flight and sales demonstrations and crew training. The FAA is workin g with civilian operators to collect technical and operational data that will help refine the UAS airworthiness certification process. The agency is currently developing a future path for safe integration of civil UAS into the NAS as part of NextGen implem entation. Read more about Civil Operations

.
The FAA has been working for several months to implement the provisions of Secti on 333 of the FAA Modernization and Reform Act of 2012, "Special Rules for Certain Unmanned Aircraft Systems," which will allow for commercial operations in low

- risk, controlled environments. Read more about Section 333

.

 Public UAS

COAs are available to public entities that want to fly a UAS in civil airspa ce. Common uses today include law enforcement, firefighting, border patrol, disaster relief, search and rescue, military training, and other government operational missions. Applicants make their request through an online process and the FAA evaluates the proposed operation to see if it can be conducted safely. Read more about Public Operations

.

 Model AircraftEH

- 4 Technical Manual

SelectTech GeoSpatial© 2015 Page 35 Recreational use of airspace by model aircraft is covered by FAA Advisory Circular 91

- 57 (PDF), which generally limits operations for hobby and recreation to below 400 feet, away from airports and air traffic, and within sight of the operator. In June 2014, the FAA published a Federal Register notice (PDF) on its interpretation of the statutory special rules for model aircraft in the FAA Modernization and Reform Act of 2012. The law is clear that the FAA may take enforcement action against model aircraft operators who operate their aircraft in a manner that end angers the safety of the national airspace system. In the notice, the FAA explains that this enforcement authority is designed to protect users of the airspace as well as people and property on the ground. Read the full press release

. Read more about Model Aircraft Operations

.